View Full Version : 2000 challenger merc 210 carb oil premix anyone?

01-17-10, 10:41 AM
Hi everyone,

I have tries to find info on going premix on my 2000 challenger 2000 I just bought. Low hours on rebuilt merc m2 jetdrive 210hp carved.

Oil injection works at this time.

What is best method to convert to premix on this engine?
Does the oil pump deliver oil to the engine in addition to injecting into te cumbustion mixture before the carbs?

Any opinions on this oil injection system reliablity vs older ( weak link in it) etc

any thoughts from someone who has done premix with this boat and engine would really be appreciated!!


01-17-10, 12:56 PM
This has come up a number of times, but as far as I can remember no one has ever come back to say what if anything they did to convert to premix. I'm sure your local Mercury parts outlet would be able to order you some sort of block off kit, but I personally like the injection set-up. You'll find that you go through a lot more oil with running premix and may get some smoke hanging around at lower power settings. The Mercury is a variable pump that runs 100:1 at idle and 50:1 at full throttle, so you'll be burning a lot more of it at idle than is really necessary.

If you do go the premix route, be sure to replace your spark plugs fairly regularly and maybe go as far as to keep a spare set on the boat along with the tools to change them. The reasoning behind that is with premix you tend to foul plugs a lot more often as compared to injection.


01-18-10, 08:42 PM
That the wear ring on these boats is not replaceable?

01-21-10, 09:40 PM
That the wear ring on these boats is not replaceable?

That is true. The Mercury (like most jets), does not use a wear ring. If you suck up any large rock and tear up the wear housing you will have to replace it to the tune of about 400 for the part. There are a few aftermarket companies that will modify, or rebuild you wear housing with either a UHM plastic, or stainless wear ring. You would have to look around in your area, but the best places to call are shops that deal in river boats. The Mercury is still about the most popular engine for the under twenty feet aluminum river boat crowd.


don't sink
02-01-10, 09:02 PM
Rookie: That would be me! I converted my Utopia 210 merc to premix and here is what I found:

-easy to do- just remove and plug all lines, disconnect low alarm beeper by tracing wiring to alarm. There is a blockoff plate for the oil injection port but I decided to wait and see if I was going to put the system back on so I did not do that step.
-premix with gas-

results: I now know that I will not lose an engine to lack of oil! However, the smoke at idle is a deal killer. I was only able to run this boat for one month last year and it came with a 42 gallon full tank of premix. It was questionable as to if it was premixed right so i doubled up on the oil to be sure. Judging by the mushroom cloud of blue...it was premixed correctly and I had now double the amount of oil I needed! So after a few weekends i started my own premix- still on the heavy side for protection.

Then I started backing off on the oil till I was down to the correct mix. And thats when the temps fell and time ran out. I never really believe I burned off all of the extra oil so the experiment is still out there. The smoke is only noticed at idle [as it should] My last outing it was acceptable and if it continues to improve I will keep premixing. If not, then the oil injection system goes back on. Sure, it costs more but I was able to get GOOD oil at $12 a gallon last year and bought enough for this upcoming summer. Thats 1/2 price and I doubt I am using twice the oil. Well, maybe the first tank!

My reason for premixing was I read too many posts about fussy alarms, air in lines and the most important fact that when this system goes south it is too late and you have done serious damage. plus mosquito's are not an issue!:ack:

02-01-10, 09:26 PM
Thanks for the info!

So the oil injector does not put oil anywhere
else important except into the carbs?

Do you leave oil in the injector pump?

Seems so much simpler than other engine premix posts!

Thanks for any clarification



02-01-10, 09:31 PM
Also, where is the source of the blockoff plate?

Does the gas/oil mix stay homogenious in such a large tank?



don't sink
02-01-10, 10:02 PM
I am not exactly sure how the engine is getting lubed [Rookie?] but it is! The Rotax engines need internal oil- ours get it from the premix or injection.

I completely disconnected the system- both tanks are out.

The block off plate source? Do you mean dealer or where it is located? And who are you calling a Homo?

never had separation issues with the oil gas mix-plus I don't keep a full tank-why lug around 40 gallons@ 7 pounds per gallon?
Thats 3 girls extra you can carry!

02-01-10, 10:12 PM

where (dealer) did you find the blockoff plate. Did you remove the injector pump? Or just leave it there with some oil in it?



02-02-10, 12:51 AM
You really need to be running a block off plate!!!

OK first the Rotax and the Mercury engine internals all get lubed the same as any two-stroke out there, by oil suspended in the fuel. Also like the Rotax, the Mercury oil pump is driven by a gear on the crankshaft. The problem lies with the fact that the only lubrication the oil pump receives is from oil passing through it on the way to the carburetors, or in the case of the fuel injected engines, the vapor separator.

Here's where things can go horribly wrong. The oil pump being driven continually with no lubrication will eventually fail, AND could possibly seize and take out the drive gear on the crank shaft resulting in a major engine failure. For this reason you absolutely must remove the oil pump and install a block off plate if you are going to go premix.

Please talk to your dealer and order the proper kit and follow any instructions that come with it. As for the oil ratio, don't just back off on the oil until it stops smoking or you will likely be to lean, also a potential source of an engine failure. Mercury recommends a mixture of 50:1 in the absence of an oil pump.


don't sink
02-02-10, 07:11 AM
Sorry, was not clear on my oil message- I was still mixing heavy and was backing off till I got to proper 100:1 mix.

As for the pump- Your thoughts are true- but I have talked to some who left it in for years now and no issues. If I do stay premix I am going to take it out though-why risk it right?

02-02-10, 10:54 AM
The proper oil ratio is 50:1, not 100:1. 100:1 is what the injection system runs it at, at idle with no load on the engine, but is far to lean for any power setting above idle. If you're going to run premix you have to run the recommended 50:1 in order to have enough lubrication at high power settings.

Also with your oil pump, at least put the engine mounted tank back in and run some sort of loop in the oil lines so that it will stay lubricated. I wouldn't take chances with a very expensive engine.


02-04-10, 03:44 PM
I am picking up the blockoff part tomorrow - hopefully it is the right one - it is only $7 and some change including o-ring...